1. Field of the invention
The present invention relates, in general, to air conditioning apparatus. In particular, the invention relates to a portable type air conditioning apparatus which includes a condenser cooled with air and water.
2. Description of the related art
A portable type air conditioning apparatus which can be moved room to room is well known, as a so-called set-free type air conditioner. The portable air conditioning apparatus typically includes a compressor, an evaporator and a condenser cooled by air and water (hereinafter referred to as a water-air cooled condenser). The portable type air conditioning apparatus also includes a water tank and a water spray device to provide water to the water-air cooled condenser. Thus, air in the room to be cooled is taken into the casing through a first air intake opening formed at the rear-upper portion of the casing. The air is cooled by the evaporator and is finally discharged to the room from an air supply opening formed at the front side of the casing.
In the above-described conventional air conditioning apparatus, air in the room is also taken into the casing through a second air intake opening formed at the rear-lower portion of the casing. The air taken into the casing flows through the water-air cooled condenser. Water stored in the water tank is also sprayed on the water-air cooled condenser. Thus, the water-air cooled condenser is cooled by the air and the water. The air flowing through the water-air cooled condenser is then exhausted to the outside of the room through a duct.
The operation of the above-described conventional air conditioning apparatus is shown in FIG. 1. The actual temperature in the room is compared with a set room temperature and the compressor is controlled on and off in response to the comparison result. The cooling capacity of the compressor is gradually increased after the compressor is energized and is rapidly decreased to zero when the compressor is de-energized. The power consumption of the compressor becomes a rated value when the compressor is energized and goes to zero when the compressor is deenergized.
In the above-described air conditioning apparatus, the pressure of the high-pressure side of the refrigerating circuit increases excessively when water in the water tank is exhausted. An increase in pressure of the high-pressure side of the refrigerating circuit adversely affects the operational life of the refrigerating circuit elements. A pressure detecting switch is used to avoid an excessive increase in pressure of the high-pressure side of the refrigerating circuit. As shown in FIG. 2, if the pressure of the high-pressure side increases above a prescribed value due to a shortage of water stored in the water tank, the pressure detecting switch is activated to stop the operation of the air conditioning apparatus, i.e., the compressor.
However, since, in general, a water consumption is increased in summer season, the air conditioning apparatus may frequently be stopped because of the late replenishment of water to the water tank during the operation.